User interface for power drive system of a patient support apparatus

ABSTRACT

A patient support apparatus includes a frame, a patient support coupled to the frame, a plurality of casters and a wheel coupled to the frame, a motor coupled to the wheel and operable to rotate the wheel to propel the patient support apparatus along a floor, and an electrical system comprising a controller configured to signal operation of the motor to rotate the wheel to propel the patient support apparatus along the floor. The electrical system further includes user inputs adjacent at least one end of the frame and adjacent at least one side of the frame. The user inputs including forward and reverse switches that are engaged to determine whether the patient support apparatus is propelled in a forward direction or a rearward direction, respectively.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/024,617, filed Feb. 10, 2011, to be issued as U.S. Pat. No.8,474,072, which is a continuation of U.S. application Ser. No.12/021,346, filed Jan. 29, 2008, now U.S. Pat. No. 7,886,377, which is acontinuation-in-part of U.S. application Ser. No. 11/865,763, filed Oct.2, 2007, now U.S. Pat. No. 7,882,582, which claims the benefit of a U.S.Provisional Patent Application No. 60/851,655, filed Oct. 13, 2006, anda U.S. Provisional Patent Application No. 60/973,805, filed on Sep. 20,2007, all of which are hereby expressly incorporated by referenceherein.

BACKGROUND

The present disclosure relates to patient support apparatuses, such ashospital beds or stretchers, and particularly to patient supportapparatuses having powered transport devices such as motorized wheels ormotorized traction drives to propel the patient support apparatus alonga floor. More particularly, the present disclosure relates to userinterfaces and control systems for such transport devices.

Some patient support apparatuses, such as hospital beds or stretchers,have powered transport devices that propel the patient support apparatusalong a floor. See, for example, U.S. Pat. Nos. 7,090,041; 7,083,012;7,021,407; 7,011,172; 7,007,765; 6,902,019; 6,877,572; 6,772,850;6,752,224; 6,749,034; 6,725,956; 6,588,523; 6,390,213; 6,330,926; and5,083,625. It is common for such devices to have controllers that areprogrammed to sense a plurality of conditions before a motor will beactivated to propel the patient support apparatus along a floor. Forexample, such devices usually sense whether or not casters are braked,whether or not an enable switch or other safety switch is engaged by auser, whether or not a battery has sufficient power to activate themotor, and whether or not an AC power plug of the patient supportapparatus is plugged into an electrical outlet. If the caster brakes areset, if the enable switch is not engaged, if the battery power is toolow, or if the AC power plug is plugged in, the powered transportdevices will typically be disabled from propelling the associatedpatient support apparatus.

Most of the known prior art transport devices of hospital beds andstretchers are configured to propel the bed only in forward and reversedirections. Such prior art transport devices usually include some typeof electrical input device, such as a potentiometer or a load cell witha strain gage output, for providing a signal that controls the speed atwhich the bed or stretcher is propelled. These electrical input devicesare generally infinitely adjustable between upper and lower limits toprovide for an infinite number of speed settings between upper and lowerlimits. However, these electrical input devices are relatively expensiveand it can sometimes be difficult for users to apply a consistent forceto a load cell, through a handle or other structure, especially whenthere is a tendency for the bed or stretcher to drive away from the userafter application of the initial driving force by the user, or to keep apotentiometer rotated to a consistent position given the fact that suchdevices are usually biased toward a neutral position in which thepowered transport device is not activated. Thus, in such patient supportapparatuses, the powered transport may feel “jerky” to the users and toany patients on the patient support apparatuses.

It has also been proposed to have a powered transport device that willallow the wheel or traction drive to be re-oriented relative to thepatient support apparatus to allow for side-to-side or lateral transportin addition to forward and reverse transport. See, for example, PCTPublication No. WO 2006/059200 A2. Having traction drives that canpropel a patient support apparatus forwardly, rearwardly, andside-to-side introduces additional complexities that need to be dealtwith in connection with user interfaces and control algorithms of suchtransport devices.

SUMMARY

The present invention comprises a patient support apparatus having oneor more of the features recited in the appended claims and/or one ormore of the following features, which alone or in any combination maycomprise patentable subject matter:

The patient support apparatus may have a frame. A patient support, suchas a single section or multi-section mattress support deck, may becoupled to the frame and may support a mattress. A plurality of castersand a wheel may also be coupled to the frame. A motor may be coupled tothe wheel and may be operable to rotate the wheel to propel the patientsupport apparatus along a floor. The patient support apparatus also mayhave an electrical system comprising a battery, recharging circuitry forthe battery, an AC power plug that is pluggable into a power outlet toprovide electrical power for recharging the battery, and a controller tocontrol operation of the motor. The controller may be configured tosignal operation of the motor to rotate the wheel to propel the patientsupport apparatus along the floor even when the AC power plug is pluggedinto a power outlet.

The patient support apparatus may be provided with a wheel supportassembly that couples the wheel to the frame. The wheel support assemblymay be operable to raise the wheel off of the floor and to lower thewheel into contact with the floor. Additionally or alternatively, thewheel support assembly may be operable to move the wheel between a firstorientation in which the motor is operable to propel the patient supportapparatus substantially parallel with a longitudinal dimension of theframe and a second orientation in which the motor is operable to propelthe patient support apparatus substantially parallel with a lateraldimension of the frame.

The electrical system may have a first user input engageable toselectively toggle among a plurality of discrete speed settings at whichthe motor is operable. The plurality of discrete speed settings maycomprise three speed settings, such as a slow speed setting, a mediumspeed setting, and a fast speed setting. The plurality of discrete speedsettings may comprise less than three or more than three speed settings.At least one of the slow speed setting, the medium speed setting, andthe fast speed setting may be faster in the forward direction than thecorresponding speed setting is in the reverse direction. Each of theplurality of discrete speed settings may correspond to a threshold speedup to which the motor is accelerated to reach over time. Theacceleration profile may be of any geometry, such as a linear ramp,discrete steps, curved, or combinations thereof.

The electrical system may have two other user inputs that are engagedsimultaneously to signal the controller to operate the motor at thediscrete speed setting selected by the first user input. Before thecontroller actually operates the motor, the controller may determine viareceived signals that the casters are unbraked and that the battery issufficiently charged. The patient support apparatus may have a pushhandle which is grippable by a user to maneuver the patient supportapparatus along the floor. The two other user inputs that are engagedsimultaneously to signal the controller to operate the motor may becoupled to the push handle. The first user input for selecting thediscrete speed setting may also be coupled to the push handle. One ormore of the user inputs may comprises switches such as membraneswitches, rocker switches, push buttons, toggle switches, or any othertype of switch, including multi-position switches.

Additionally or alternatively, the electrical system may comprisefurther user inputs adjacent to one or both sides of the frame to signalthe controller to operate the motor to propel the patient supportapparatus laterally when the wheel is in the appropriate orientation forlateral or side-to-side powered transport. These further user inputs maybe coupled to siderails which are mounted to the frame. These furtheruser inputs may also be used to propel the patient support apparatus inforward and/or reverse directions. The user inputs coupled to the pushhandles, typically located at the head end of the frame, may also beusable to propel the patient support apparatus in left and right lateraldirections and in forward and reverse longitudinal directions.Additionally or alternatively, the electrical system may compriseanother set of user inputs located at the foot end of the frame, such ason a foot end frame member. The user inputs at the foot end of the framealso may be used to propel the patient support apparatus in left andright lateral directions and in forward and reverse longitudinaldirections.

One or more of the user inputs located at the ends and/or sides of thepatient support apparatus may further comprise at least one additionalswitch that is engaged to signal the controller to move the wheelbetween the first orientation and the second orientation. One or more ofthe user inputs located at the ends and/or sides of the patient supportapparatus may have a forward switch, a reverse switch, a left switch anda right switch that, when engaged simultaneously with a respectiveadditional switch (sometimes referred to by those skilled in the art asa “deadman switch”), signal the controller to operate the motor topropel the patient support apparatus in the forward, reverse, left, andright directions, respectively.

A patient support apparatus may comprise a frame, a patient supportcoupled to the frame, a push handle coupled to the frame and having ahandle post, and a user interface coupled to the handle post and havingat least one user input. The user interface may be rotatable about anaxis defined by the handle post between a first position presenting theat least one user input to a caregiver standing at an end of the frameand a second position presenting the at least one user input to acaregiver standing alongside the frame.

The patient support apparatus may further comprise a power transportsystem coupled to the frame and operable to propel the patient supportapparatus along a floor. The at least user interface may be engageableto provide a signal to the power transport system to propel the patientsupport apparatus along the floor.

Additional features, which alone or in combination with any otherfeature(s), such as those listed above, may comprise patentable subjectmatter and will become apparent to those skilled in the art uponconsideration of the following detailed description of variousembodiments exemplifying the best mode of carrying out the embodimentsas presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a patient support apparatusshowing a pair of push handles coupled to a head end of a frame, theframe supporting a mattress and mattress support deck underlying themattress, a pair of siderails along the sides of the frame moved toraised positions, and push buttons of an electrical system of thepatient support apparatus coupled to distal ends of the push handles;

FIG. 2 is a side perspective view of the patient support apparatus ofFIG. 1 showing a motorized drive wheel of a powered transport devicesituated beneath a shroud which covers a base frame portion of the frameand showing a user interface coupled to one of the siderails;

FIG. 3 is a block diagram of the electrical system of the patientsupport apparatus showing a controller and an optional main powerswitch, a user interface, a power supply, a raise/lower actuator, aswivel actuator, a drive motor, and a caster brake position sensor eachcoupled to the controller;

FIG. 4 is an enlarged perspective view of a grip handle area of one ofthe push handles;

FIG. 5A is an exploded perspective view of one of the push handleassemblies showing a forward switch and a reverse switch arranged forcoupling to a switch housing, a switch housing tube above the switchhousing, a compression gasket to the right of the upper region of theswitch housing tube, a bent handle tube to the right of the compressiongasket, an actuator lever to the right of the bottom region of the benthandle tube, and a pivot pin arranged for insertion through respectiveapertures in the actuator lever, the bent handle tube, the compressiongasket and the switch housing tube;

FIG. 5B is an enlarged perspective view, with portions broken away,showing the actuator lever received in the switch housing tube andhaving a lower end that interfaces with the forward switch and thereverse switch;

FIG. 6 is an enlarged front plan view of a user interface that couplesto one of the push handles showing the user interface having a speedselection button beneath three horizontally arranged speed indicatorLED's near the top of the user interface, a left direction button and aright direction button beneath the speed selection button, and fivehorizontally arranged battery power indicator LED's beneath the left andright arrow buttons;

FIG. 7 is an enlarged side plan view of the user interface coupled tothe siderail of the patient support apparatus showing this userinterface having a right button, a left button, an enable key button, aforward button, and a reverse button on a generally vertically orientedsurface of a button housing of the user interface;

FIG. 8 is a top perspective view of a the user interface of FIG. 7showing an upwardly facing surface of the button housing of the userinterface having left, right, forward, and reverse indicia generallyaligned with the corresponding left, right, forward, and reverse buttonsthat are on the vertically oriented surface of the button housing;

FIG. 9 is an end perspective view of the patient support apparatusshowing an additional user interface coupled to a frame member at a footend of the frame;

FIG. 10 is an enlarged top plan view of the additional user interfaceshowing an upwardly facing surface of a button housing of this userinterface having a left button, a right button, an enable key button, aforward button, and a reverse button;

FIG. 11 is a perspective view of another embodiment of the poweredtransport device of FIG. 2 showing a drive wheel extending through anopening in a cover of the powered transport device;

FIG. 12A is an exploded perspective view of the powered transport deviceof FIG. 11 showing the cover, a drive wheel assembly including the drivewheel above the cover, a drive wheel motor to the right of the drivewheel assembly, a drive wheel raise/lower assembly to the left of thedrive wheel assembly, a raise/lower motor above the drive wheelraise/lower assembly, a swivel assembly including an indexing motor tothe right of the raise/lower motor, a mounting plate assembly above theraise/lower motor and the swivel assembly, and a gas spring to the leftof the mounting plate assembly;

FIG. 12B is a bottom view, with the cover removed, of the poweredtransport device of FIGS. 11-12;

FIG. 13 is a perspective view of another embodiment of the push handleassembly of FIGS. 5A and B;

FIG. 14 is an exploded perspective view of the push handle assembly ofFIG. 13 showing a bumper, a mounting bracket above the bumper thatcouples to the upper frame of the patient support apparatus, a straingage assembly above the mounting bracket, a strain gage assembly shieldabove the strain gage assembly, bellows above the strain gage assemblyshield, a push handle above the bellows, a longitudinally-extendingpivot pin to the left of a top portion of the strain gage assembly andarranged for insertion through the upwardly-opening slots in the shield,through the apertures in the strain gage assembly and then throughelongated slots in the push handle, an enable switch actuator to theleft of a bent portion of the push handle, and a push handle userinterface coupled to an upper end of the bent portion of the pushhandle;

FIG. 15 is an exploded perspective view of the push handle of FIGS.13-14 showing a bent tube, an enable switch housing above a bent portionof the bent tube, an enable switch and a connector to the right of theenable switch housing, a handle grip above the enable switch housing, apush handle user interface top housing above the handle grip, a pushhandle user interface bottom housing to the right of the user interfacetop housing, and a push handle user interface overlay to the left of theuser interface top housing;

FIG. 16 is an enlarged front plan view of another embodiment of the pushhandle user interface of FIG. 6 showing the user interface having aspeed selection button beneath three arcuately arranged speed indicatorLED's near the top of the user interface, the speed selection buttonhaving an indicia showing a caregiver pushing a stretcher, a servicerequired LED to the right of the speed selection button, a leftdirection button and a right direction button beneath the speedselection button, a stretcher orientation indicia between the left andright direction buttons, two LED's adjacent the respective left andright direction buttons, and battery power indicator LED's beneath theleft and right direction buttons;

FIG. 17 is an enlarged front plan view of still another embodiment ofthe push handle user interface similar to the push handle user interfacein FIG. 16, except that the speed selection button is omitted in theuser interface of FIG. 17;

FIG. 18 is a front plan view of another embodiment of the left siderailuser interface of FIG. 7 showing the user interface having left, right,forward, and reverse direction buttons arranged about an indicia showinga caregiver standing adjacent one of the sides of a stretcher, fourLED's adjacent the respective left, right, forward and reverse directionbuttons, a service required LED to the upper left of the left, right,forward and reverse direction buttons, an enable key button to the lowerleft of the left, right, forward and reverse direction buttons, an LEDadjacent the enable key button, battery power indicator LED's to theupper right of the left, right, forward and reverse direction buttons,the buttons and the indicia being arranged on a generally verticallyoriented surface of a user interface housing coupled to the associatedsiderail;

FIG. 19 is a front plan view of a right siderail user interface similarto the left siderail user interface of FIG. 18;

FIG. 20 is a perspective view, with portions broken away, of the pushhandle assembly of FIGS. 13-15 showing the push handle folded downwardlyabout a pivot pin to a stowed position after the push handle is firstpulled upwardly;

FIG. 21 is a perspective view, with portions broken away, of anotherembodiment of the push handle assembly of FIGS. 13-15 showing a lowerend of the push handle having a tapered sleeve which is configured to bereceived in a tapered socket formed in an upper region of the straingage assembly, the opposite sidewalls of the tapered sleeve of the pushhandle having elongated generally helical slots for receiving thelongitudinally-extending pivot pin extending through the oppositesidewalls of the strain gage assembly, the pivot pin sliding within theelongated generally helical slots to allow the push handle to be pulledupwardly and then folded downwardly to a folded stowed position and toallow the push handle to be pivoted upwardly and then lowered downwardlyinto the socket to an upright use position, the push handle turninginwardly about a vertical axis into a more ergonomic position for acaregiver as the push handle is lowered into the socket to the uprightuse position after it is first moved to a generally vertical positionfrom the folded stowed position;

FIG. 22 is a front elevation view of the tapered sleeve showing thehelical slots in the opposite sidewalls of the tapered sleeve, thehelical slot in the back wall being shown in phantom;

FIG. 23 is an end elevation view of the tapered sleeve showing a pair ofcutouts or reliefs in the opposite sidewalls of the tapered sleeve forallowing the wires from the push handle enable switch and the wires fromthe push handle user interface to pass through when the push handle isfolded down;

FIG. 24 is a front elevation view of the upper portion of the straingage assembly showing the tapered socket in phantom;

FIG. 25 is an end elevation view of the upper portion of the strain gageassembly showing a cutout or relief formed in the upper portion of thestrain gage assembly to allow the push handle to pivot downwardly to thefolded stowed position;

FIG. 26 is a perspective view of still another embodiment of the pushhandle assembly of FIGS. 13-15;

FIG. 27 is a partially exploded perspective view of the push handleassembly of FIG. 26 showing an SPDT switch assembly disposed between anupper portion of the push handle and a lower portion of the push handle;

FIG. 28 is an enlarged perspective view of the SPDT switch assembly ofFIG. 27;

FIG. 29 is an exploded perspective view of the SPDT switch assembly ofFIGS. 27-28 showing a switch housing, an SPDT switch to the left of theswitch housing, a slider below the switch housing, and retainer belowthe slider;

FIG. 30 is a perspective view of a push handle user interface, similarto the user interface shown in FIGS. 16 and 17, coupled to a handle postof a push handle located at the head end of the apparatus on the rightside thereof showing the user interface facing generally rearwardly sothat a caregiver standing at the head end of the apparatus can grasp thehandle post with her right hand as shown, for example, in FIG. 32 andoperate the controls on the right hand user interface with her rightthumb;

FIG. 31 is a perspective view, similar to FIG. 30, showing the pushhandle user interface facing generally upwardly so that a caregiverstanding alongside the right side of the apparatus can grasp the handlepost with her left hand as shown, for example, in FIG. 33 and operatethe controls on the right hand user interface with her left thumb;

FIG. 32 is a perspective view of the apparatus showing a caregiverstanding at the head end of the apparatus with her hands on the handleposts of the push handles so that she can operate the controls on one ofthe user interfaces with her thumb;

FIG. 33 is a perspective view, similar to FIG. 32, of the apparatusshowing a caregiver standing alongside the right side of the apparatuswith her left hand on the handle post of the push handle so that she canoperate the controls on the user interface with her thumb;

FIGS. 34 and 35 are exploded perspective views showing top and bottomhalves of the user interface housing arranged on opposite sides of thehandle post to which they are secured by suitable fasteners; and

FIGS. 36-38 are top, end and side views showings the angles between thehandle post carrying the user interface and the lateral, horizontal andlongitudinal axes.

DETAILED DESCRIPTION OF THE DRAWINGS

As shown in FIGS. 1-2 and 4, a patient support apparatus 10, such as astretcher shown in FIGS. 1-2 or a hospital bed shown in FIGS. 32-33,includes a frame 12 which has an upper frame 14 and a base frame orlower frame 16 interconnected by elevation adjustment mechanisms 18 thatare operable to raise, lower, and tilt upper frame 14 relative to thelower frame 16 as shown in FIGS. 1 and 2. A patient support 20, such anarticulating deck, is coupled to upper frame 14. A mattress 22 iscarried by patient support 20. A plurality of casters 23 are coupled tobase frame 16 and are in contact with the underlying floor 150 as shownin FIG. 9. Casters 23 include braking mechanisms (not shown) which arewell known in the art and apparatus 10 has a set of brake/steer pedals21 which are movable to brake and unbrake the casters 23 viamanipulation of the associated caster braking mechanisms. The apparatus10 has a head end 152, a foot end 154, a left side 156, a right side158, a longitudinal axis 160, and a transverse or lateral axis 162.

A powered transport device 24 is coupled to base frame 16 and includes awheel 26 that is motor driven to propel apparatus 10 along a floor. Inone embodiment, device 24 is of the type available from BorringiaIndustrie AG of Ettingen, Switzerland, one version of which is marketedas the COMPASS™ drive. Such a device 24, therefore, may be constructedin accordance with the teachings of PCT Patent Application No. PCTPublication No. WO 2006/059200 A2 which is hereby incorporated byreference herein and which has a motor driven wheel that can be raisedout of contract with the floor, lowered into contact with the floor, andswiveled by ninety degrees between a first orientation in whichapparatus 10 is propelled in the longitudinal direction (i.e., parallelwith the longitudinal or long dimension 160 of frame 12) and a secondorientation in which apparatus 10 is propelled side-to-side or in thelateral direction (i.e., parallel with the lateral or short dimension162 of frame 12).

An electrical system 28 of apparatus 10 includes a controller 30 and anoptional main power switch 32, one or more user interfaces 34, a powersupply 36, a raise/lower actuator 38, a swivel actuator 40, a drivemotor 42, and a caster brake position sensor 44, each of which iscoupled to the controller 30. Controller 30 comprises logic-basedcircuitry such as a microprocessor, a microcontroller, a fieldprogrammable gate array, or even discrete logic gates or the like, alongwith all associated circuitry such as memory, analog-to-digitalconverters, digital-to-analog converters, input/output circuitry and soon. The circuitry of controller 30 may be located on a plurality ofcircuit boards or be included in various modules that couple together.For example, controller 30 may include a logic controller portion whichreceives input signals regarding various conditions of apparatus 10 anda drive controller portion that is coupled to the logic controllerportion and that controls voltage and/or current application to motor 42and actuators 38, 40 of system 28 in response to an output signalreceived from the logic controller portion. In those embodiments havingmain power switch 32, this switch 32 is used to turn the transportdevice 24 on and off. In those embodiments without main power switch 32,then transport device may be on continually, although the system maypower down into a sleep mode after a period of inactivity. In someembodiments, when off or when in the sleep mode, transport device 24have wheel 26 in a raised position spaced from the underlying floor.

As shown in FIG. 3, the one or more user interfaces 34 include userinputs, as will be further described below, that are engaged by a userto signal controller 30 as to the manner in which transport device 24 isto be operated. Power supply 36 comprises a battery, battery rechargingcircuitry, an AC power cord 35 having an AC power plug 37, AC-to-DCconversion circuitry and other circuit components involved in poweringthe remainder of system 28. Actuator 38 is operable in response tocommand signals from controller 30 to raise wheel 26 off of theunderlying floor and to lower wheel 26 into contact with the floor.Actuator 40 is operable in response to command signals from controller30 to swivel wheel 26 between the first and second orientations. Drivemotor 42 is operable in response to command signals from controller 30to rotate wheel 26 thereby to propel apparatus 10 along the floor.

Assuming controller 30 receives signals from user interface 34indicating that a user desires powered transport of apparatus 10,controller 30 determines whether other conditions are met prior toactivating motor 42 to drive wheel 26. For example, controller 30 willfirst determine that battery power of power supply 36 meets or exceeds athreshold level and will also determine whether casters 23 are unbrakedbefore applying power to drive motor 42 to rotate wheel 26. Caster brakeposition sensor 44 provides a signal to controller regarding whethercasters 23 are braked or unbraked. Contrary to the teachings of allknown prior art patient support apparatuses that have powered transportsystems and that have AC power plugs, controller 30 does not requirethat the power plug of power supply 36 of apparatus 10 be unpluggedprior to applying power to drive motor 42 to rotate wheel 26 to propelapparatus 10 along the floor. This creates the possibility thatapparatus 10 can be power driven with the power plug still plugged intoan electrical outlet resulting in the power plug being ripped out of theelectrical outlet as apparatus 10 is driven away. However, by allowingmotor 42 to be driven even when the AC power plug is plugged into anelectrical outlet, powered transport device 24 can be used to make minoradjustments in the positioning of apparatus within its location. This isespecially useful when obese or morbidly obese (also known as,bariatric) patients are supported on apparatus 10.

In the illustrative embodiment, apparatus 10 has user interfaces 34 atthe head end 152, foot end 154, and both sides 156, 158 of the frame 12.In other embodiments, user interfaces 34 may be provided at lesserlocations, including having user interface 34 at only one such location.User interface 34 at the head end of apparatus 10 includes a pair offirst switches 44, shown in FIGS. 1 and 4, that extend from distal ends46 of hand grip portions 48 of respective push handles 50 that arecoupled to upper frame 14. User interface 34 at the head end ofapparatus 10 further includes a forward switch 52 and a reverse switch54 that are situated within an interior region of the associated pushhandle 50 as shown in FIGS. 5A and 5B. Although only one push handle 50is shown in FIGS. 5A and 5B, it is understood that both push handles 50are constructed similarly with one push handle 50 being substantiallythe mirror image of the other one. Thus, the description that follows ofone push handle 50 is applicable to both.

Push handle 50 has a switch housing 56 to which switches 52, 54 arecoupled as shown in FIGS. 5A and 5B. Electrical wires (not shown)extending from switches 44, 52, 54 are routed out of push handle 50through the bottom of switch housing 56 and are routed to controller 30along portions of frame 12. Switch housing 56 is received in a lowerregion of a switch housing tube 58. Handle 50 includes a bent tube 60,part of which comprises gripping portion 48 and part of which comprisesa generally vertical portion 62. An actuator lever 64 is coupled to thebottom region of vertical portion 62 of push handle 50. Lever 64 and thebottom region of vertical portion 62 of push handle 50 are received inthe upper portion of the interior region of switch housing tube 58 withan annular compression gasket 66 situated between the bottom region ofvertical portion 62 of handle 50 and upper region of tube 58. A pivotpin 67 extends through associated apertures in tube 58, portion 62,lever 64, and compression gasket 66 to couple these elements together.Actuator lever 64 extends downwardly from portion 62 within compressiongasket 66 and is sized such that a tip 68 of lever 64 interfaces withswitches 52, 54 as shown in FIGS. 5A and 5B.

Bent tube 60 is pivotable by a slight amount about pin 67 relative toswitch housing tube 58. Compression gasket 66 keeps tube 60 from tooloosely rattling within tube 58, but is compressible to allow thepivoting movement of tube 60 relative to tube 58 when a user applies asufficient amount of force to gripping portion 48 of push handle 50.When the user pushes gripping portion 48 in a forward direction, tip 68of lever 64 engages switch 52 to turn it from an off position to an onposition. When the user pulls gripping portion 48 in a rearwarddirection, tip 68 of lever 64 engages switch 54 to turn it from an offposition to an on position. When the user lets go of gripping portion48, compression gasket 66 returns tube 60 to a neutral position havingboth switches 52, 54 in the respective off positions.

To propel apparatus in a forward direction (i.e., having the foot end ofapparatus 10 leading the way), a user must press at least one of the twoswitches 44 extending from ends 46 of gripping portions 48 of pushhandles 50 while simultaneously applying sufficient pushing force to atleast one of handles 50 to cause the associated lever 64 to turn switch52 to the respective on position. If all other necessary conditions aremet, as determined by controller 30, then controller 30 will apply powerto motor 42 to rotate wheel 26 in a first direction to propel apparatus10 forwardly in response to one of switches 44 and one of switches 52 ofuser interface 34 at the head end of apparatus 10 being simultaneouslyengaged or turned on by the user.

To propel apparatus in a rearward direction (i.e., having the head endof apparatus 10 leading the way), a user must press at least one of thetwo switches 44 extending from ends 46 of gripping portions 48 of pushhandles 50 while simultaneously applying sufficient pulling force to atleast one of handles 50 to cause the associated lever 64 to turn switch54 to the respective on position. If all other necessary conditions aremet, as determined by controller 30, then controller 30 will apply powerto motor 42 to rotate wheel 26 in a second direction, opposite the firstdirection, to propel apparatus 10 rearwardly in response to one ofswitches 44 and one of switches 54 of user interface 34 at the head endof apparatus being simultaneously engaged or turned on by the user.

Referring now to FIG. 6, the user interface 34 at the head end ofapparatus 10 also includes a speed selection button 70. Subsequentpresses of button 70 selectively toggles among a plurality of discretespeed settings at which the motor 42 is operable. In the illustrativeembodiment, button 70 has a tortoise indicia 72 and a hare indicia 74over portions of button 70. Button 70 can be pressed over the tortoiseindicia 72 to toggle the speed down, while button 70 can be pressed overthe hare indicia 74 to toggle the speed up. In other embodiments, button70 may simply scroll in one direction and then cycle back to thebeginning of the series after the highest, or lowest, setting isreached. In some embodiments, button 70 comprises a membrane switch or apair of membrane switches, one for toggling the speed up and one fortoggling the speed down.

In the illustrative example, the plurality of discrete speed settingsincludes a slow speed setting, a medium speed setting, and a fast speedsetting. As such, the user interface 34 shown in FIG. 6 has three speedindicator LED's 76 to visually indicate the selected speed setting. Forexample, in the slow speed setting, the left-most LED 76 is on or litand the other two LED's are off or unlit; in the medium speed settingthe left-most LED 76 and the middle LED 76 are on and the right-most LED76 is off; and in the high speed setting, all three LED's are on. Ofcourse, if there are more or less then three speed settings, acorresponding number of lesser or greater LED's 76 are provided on theassociated user interface 76. In some embodiments, however, userinterface 34 includes a numeric display to visually indicate theselected speed setting.

With regard to the forward/reverse operation of powered transport device24 in some embodiments, at least one of the slow speed setting, themedium speed setting, and the fast speed setting results in apparatus 10being propelled faster in the forward direction than the correspondingspeed setting results in apparatus 10 being propelled in the reversedirection. In such embodiments, therefore, controller 30 signals drivemotor 42 to operate more slowly for a particular speed setting in thereverse direction than in the forward direction. In other embodiments,the slow, medium, and fast speed settings may have substantially thesame respective speeds in the forward and reverse directions. It will beappreciated that each of the plurality of discrete speed settingscorresponds to a threshold speed up to which motor 42 is accelerated toreach over time. The acceleration profile may be of any geometry, suchas a linear ramp, discrete steps, curved, or combinations thereof.

The user interface 34 shown in FIG. 6 also includes a left directionbutton 78 and a right direction button 80 that are both positionedgenerally beneath speed selection button 70. Assuming all of the othernecessary conditions are met, including pressing one of switches 44,then pressing button 78 results in apparatus 10 being propelled bypowered transport device 24 laterally in the left direction, whereaspressing button 80 results in apparatus 10 being propelled by poweredtransport device 24 laterally in the right direction. The left and rightdirections are determined from the vantage point of a user standingadjacent a head end of apparatus 10 and facing toward the apparatus orfrom the vantage point of a patient lying in a supine or face upposition on mattress 22 with their head near the head end of apparatus10. A stretcher orientation indicia 82 is provided between buttons 78,80 to provide the user with a visual indication as to the direction thatapparatus 10 will be propelled in response to buttons 78, 80 beingpressed as shown in FIG. 6.

If wheel 26 is in the first orientation when one of buttons 78, 80 ispressed simultaneously with switch 44, then controller 30 will commandswivel actuator 40 to move wheel 26 from the first orientation to thesecond orientation prior to commanding motor 42 to rotate wheel 26 topropel apparatus 10 leftward or rightward as the case may be. Similarly,if wheel 26 is in the second orientation when one of switches 52, 54 isactuated simultaneously with switch 44, then controller 30 will commandswivel actuator 40 to move wheel 26 from the second orientation to thefirst orientation prior to commanding motor 42 to rotate wheel 26 topropel apparatus forward or rearward as the case may be. Two LED's 84are located adjacent respective buttons 78, 80 and are on or lit whenthe corresponding button 78, 80 is pressed to provide a feedback to theuser.

In some embodiments, however, LED's 84 are on or lit when wheel 26 is inthe second orientation and are off when wheel 26 is in the firstorientation. In such embodiments, LED's 84 provide a visual indicationas to the orientation of wheel 26. Based on the status of LED's 84, auser can determine whether to expect a slight delay after attempting topropel apparatus 10 due to wheel 26 being re-oriented from the firstorientation to the second orientation, or vice versa. In someembodiments, the speed setting in the left and right directions defaultsto the low speed setting regardless of what speed setting is otherwiseselected using button 70 for the forward and reverse directions. Ofcourse, having slow, medium, and fast settings for the left and rightdirections are contemplated by this disclosure.

The user interface 34 shown in FIG. 6 has a battery indicia 86 and fiveLED's 88 that are lit from left to right to indicate the amount ofcharge in the battery of power supply 36. When all five LED's 88 arelit, the battery is fully charged and when no LED's 88 are lit, thebattery is essentially drained of charge. In other embodiments, more orless LED's 88 than five may be provided, including having no LED's 88 atall. In some embodiments, however, user interface 34 shown in FIG. 6includes a numeric display to visually indicate the amount of charge inthe battery of power supply 36.

In some embodiments, the user interface 34 of FIG. 6 is provided on aninterface housing (not shown) that is coupled to one of push handles 50,such as being coupled to grip handle portion 48 near, or on, the distalend 46 thereof. To allow for this, switch 44 is moved to a differentlocation on grip handle portion 48, such as being positioned on thebottom surface of portion 48 or on the surface of portion 48 that facestoward the foot end of apparatus 10. By locating switch 44 at one ofthese alternative locations on grip handle portion 48 and by locatingthe interface housing adjacent distal end 46 of grip handle portion 48,a user is able to grasp portion 48 with his or her fingers and engageswitch 44 while also using his or her thumb to engage buttons 70, 78, 80as desired.

In some embodiments, the interface housing coupled to handle 50 isconfigured so that the user interface 34 of FIG. 6 faces away frommattress 22 and toward a user standing at the head end of apparatus 10.In other embodiments, the user interface 34 of FIG. 6 may be coupled toa portion of upper frame 12 at the head end of apparatus 10 rather thanbeing coupled to one of push handles 50.

As shown in FIGS. 2 and 7, apparatus 10 has left and right siderails 90and an additional user interface 34 coupled to each of the siderails 90.The user interfaces 34 on siderails 90 are provided on respective userinterface housings 92 that are coupled to associated top rails 94 of therespective siderails 90. Only one of the user interfaces 34 coupled tosiderails 90 is described below, it being understood that both userinterfaces 34 coupled to siderails 90 are substantially similar.

User interface 34 coupled to siderail 90 includes a right directionbutton 96, a left direction button 98, an enable key button 100, aforward direction button 110, and a reverse direction button 112 on agenerally vertical surface 113 of housing 92 as shown in FIG. 7. In theillustrative embodiment, each of buttons 96, 98, 100, 110, 112 comprisesa membrane switch. It is within the scope of this disclosure for othertypes of buttons or switches to be used, such as rocker switches, toggleswitches, push button switches, and so on, as well as using atouchscreen or other type of touch sensor, in lieu of the membraneswitches that embody buttons 96, 98, 100, 110, 112 in the illustrativeexample.

In some embodiments, by simultaneously pressing or engaging the enablekey button 100 along with one of the other direction buttons 96, 98,110, 112, apparatus 10 will be propelled by device 24 in the associateddirection assuming all other necessary conditions are met. Thus,simultaneous engagement of buttons 96, 100 signals controller 30 topropel apparatus 10 laterally to the right; simultaneous engagement ofbuttons 98, 100 signals controller 30 to propel apparatus 10 laterallyto the left; simultaneous engagement of buttons 100, 110 signalscontroller 30 to propel apparatus 10 forwardly; and simultaneousengagement of buttons 100, 112 signals controller 30 to propel apparatus10 rearwardly.

A first stretcher orientation indicia 114 is located near one end of theuser interface 34 of FIG. 7 to provide the user with a visual indicationas to the direction that apparatus 10 will be propelled in response tobuttons 96, 98 being pressed along with button 100. A second stretcherorientation indicia 116 is located near the other end of the userinterface 34 of FIG. 7 to provide the user with a visual indication asto the direction that apparatus 10 will be propelled in response tobuttons 110, 112 being pressed along with button 100. In someembodiments, such as the illustrative embodiment, a momentary press ofbutton 100 may set a time period, such as 2 to 5 seconds, within whichpressing any of buttons 96, 98, 110, 112 individually signals controller30 to propel apparatus 10 in the associated direction. An LED 118 isprovided on button 100 and is on or lit during the time period thatbuttons 96, 98, 110, 112 are usable to propel apparatus 10 in thecorresponding direction. A battery charge indicator 120 is also includedin the user interface 34 of FIG. 7 and is lit in an appropriate manner,such as via a set of vertically stacked bars, to indicate the amount ofcharge in the battery of power supply 36.

Referring now to FIG. 8, an upwardly facing surface 122 of interfacehousing 92 has a right direction indicia 124, a left direction indicia126, a forward direction indicia 128, and a reverse direction indicia130. Each indicia 124, 126, 128, 130 is generally aligned with thecorresponding left, right, forward, and reverse direction buttons 96,98, 110, 112 that are on the generally vertical surface 113 of housing92. Therefore, indicia 124, 126, 128, 130 provides a visual indicationto a user standing alongside siderail 90 and looking downwardly athousing 92 as to the general location of buttons 96, 98, 110, 112.

In the illustrative example, no provision is made on the user interface34 coupled to siderail 90 for any type of speed adjustment. In otherembodiments, a speed selection button, similar to button 70 of the userinterface at the head end of apparatus 10, may be provided on the userinterface 34 coupled to siderail 90. Users propelling apparatus 10 whenstanding alongside one of siderails 90 may not have as much control overthe maneuverability and steering of apparatus 10 as users propellingapparatus 10 when gripping push handles 50. Thus, in some embodiments,when the user interface 34 coupled to siderail 90 is used to propelapparatus 10, controller 30 defaults to the slow speed settingregardless of what speed setting may have otherwise been selected withbutton 70 at the head end of apparatus 10. In other embodiments, withregard to the user interface 34 on siderail 90, the medium speed settingmay be the default setting for the forward and reverse directions,whereas the low speed setting may be the default setting for the leftand right directions.

As shown in FIGS. 9 and 10, upper frame 14 of apparatus 10 has alaterally extending frame member 132 located near the foot end ofapparatus 10 and yet another user interface 34 is coupled to this framemember 132. The user interface 34 at the foot end of apparatus 10 isprovided on a user interface housing 134 that is coupled to frame member132. The user interface 34 coupled to frame member 132 is substantiallythe same as the user interface 34 coupled to siderail 90. Thus, likereference numerals are used to denote like elements of these userinterfaces 34 and the description above of the user interface 34 ofFIGS. 2 and 7 is equally applicable to the user interface of FIGS. 9 and10 and is not repeated. One main difference between the user interface34 of FIGS. 9 and 10 is that it is located on an upwardly facing surface136 of interface housing 134, whereas user interface 34 of FIGS. 2 and 7is located on generally vertical surface 113 of interface housing 92.Another difference is that there is no direction arrow indicia onhousing 134 like that found on surface 122 of housing 92.

As indicated above, the powered transport device or system 24 (FIG. 2)has the motor driven wheel 26 that can be raised out of contract withthe floor 150, lowered into contact with the floor 150, and swiveled byninety degrees between the first orientation in which apparatus 10 ispropelled in the longitudinal direction 160 and the second orientationin which apparatus 10 is propelled side-to-side or in the lateraldirection 162. An alternative powered transport device 200 is shown inFIGS. 11, 12A, and 12B. The device 200 comprises a mounting assembly 202that includes a stationary mounting plate 204 coupled to the undersideof the lower frame 16 of the apparatus 10 and a rotatable platform 206coupled to the underside of the mounting plate 204 for pivoting movementabout a generally vertical axis 208.

With the exception of a ring gear (not shown) and stops 388, 390 (FIG.12A) attached to the stationary mounting plate 204, the components ofthe device 200 are supported by the rotatable platform 206 for rotationtherewith about the vertical axis 208 between a first orientation inwhich the device 200 is operable to propel the apparatus 10substantially parallel with the longitudinal dimension 160 of the frame12 and a second orientation in which the device 200 is operable topropel the apparatus 10 substantially parallel with the lateraldimension 162 of the frame 12. In the illustrative embodiment, both themounting plate 204 and the rotatable platform 206 are generallycircular. In other embodiments, however, the mounting plate 204 and therotatable platform 206 may have other shapes, such as square,rectangular, triangular, oval, etc.

As shown in FIGS. 12A, and 12B, the device 200 includes a drive wheelassembly 222 that extends downwardly from the rotating platform 206 andcoupled thereto for rotation therewith about the vertical axis 208. Thedrive wheel assembly 222 includes a wheel-mounting bracket 224 thatcarries a drive wheel 226 at a first end for rotation about a generallyhorizontal first shaft 230 (FIG. 12B). At a second end, thewheel-mounting bracket 224 is coupled to a pair of vertically-extendingspaced-apart flanges 232, 234 for pivoting movement about a generallyhorizontal second shaft 236, which is generally parallel to the firstshaft 230. As shown in FIG. 12A, the flanges 232, 234 extend downwardlyfrom the rotatable platform 206. An endless chain (not shown) is trainedabout respective sprockets 240, 242 mounted on associated shafts 230,236 to establish a driving connection therebetween.

The drive wheel assembly 222 further includes a drive wheel motor 244that has an output shaft 246. The drive wheel motor 244 is supported bya vertically-extending flange 248 that extends downwardly from therotating platform 206 and coupled thereto for rotation therewith. Anendless chain (not shown) is trained about respective sprockets 250, 252mounted on associated shafts 236, 246 to establish a driving connectiontherebetween. The drive wheel motor 244 is operable in response tocommand signals from the controller 30 (FIG. 3) to rotate the wheel 226to propel the apparatus 10 along the floor 150.

When the rotating platform 206 is in the first or longitudinalorientation, the wheel 226, which is supported by the rotating platform206, is also in the first or longitudinal orientation. When the wheel226 is in the first or longitudinal orientation, the device 200 isoperable to propel the apparatus 10 substantially parallel with thelongitudinal dimension of the frame 12. Also, when the rotating platform206 and the wheel 226 are in their respective first or longitudinalorientations, the shafts 230, 236, 246 extend laterally or transverselyrelative the frame 12. On the other hand, when the rotating platform 206is in the second or lateral orientation, the wheel 226 is also in thesecond or lateral orientation. When the wheel 226 is in the second orlateral orientation, the device 200 is operable to propel the apparatus10 substantially parallel with the lateral dimension of the frame 12. Inaddition, when the rotating platform 206 and the wheel 226 are in theirrespective second or lateral orientations, the shafts 230, 236, 246extend longitudinally relative the frame 12.

Referring to FIGS. 12A, and 12B, the device 200 includes a drive wheelraise/lower assembly 260 that extends downwardly from the rotatingplatform 206 and coupled thereto for rotation therewith about thevertical axis 208. The raise/lower assembly 260 is operable in responseto command signals from the controller 30 (FIG. 3) to move the wheel 226between a storage position spaced from the underlying floor and a useposition in engagement with the underlying floor. The raise/lowerassembly 260 includes a raise/lower motor 262 having an output shaft 264and a linear actuator 266 having an input shaft 268. The two shafts 264,268 of the raise/lower assembly 260 are generally parallel to each otherand parallel to the shafts 230, 236, 246 of the drive wheel assembly 222as shown in FIG. 12B. An endless chain (not shown) is trained aboutrespective sprockets 270, 272 mounted on associated shafts 264, 268 toestablish a driving connection therebetween. The raise/lower motor 262and the actuator 266 are supported by a pair of vertically-extendingspaced-apart flanges 274, 276 that extend downwardly from the rotatingplatform 206. The actuator 266 includes a cylindrical housing 278 thatis rotatable relative to the flanges 274, 276 about a central axis 282of the housing 278. In addition, the actuator 266 has an output member280 that extends out of and retracts into the housing 278 in response tothe operation of the raise/lower motor 262. The extension and retractionof the output member 280 is converted into an up/down motion of thewheel-mounting bracket 224, and, in turn, an up/down motion of the wheel226, via a linkage 290.

Continuing reference to FIGS. 12A and 12B, the linkage 290 includes arotatable flapper mount 292 and a connecting link 294. The mount 292 iscoupled to the housing 278 of the actuator 266 for rotation therewithabout the axis of rotation 282 of the housing 278. The connecting link294 is pivotably coupled at a first end to the mount 292 and pivotablycoupled at a second end to a lug 300 (FIG. 12A) that extends upwardlyfrom the wheel mounting bracket 224. Referring to FIG. 12A, when thehousing 278 pivots in a clockwise direction 300 (when viewed from theleft hand side in FIG. 12A), the connecting link 294 moves in a leftwarddirection 302 away from the wheel mounting bracket 224, the wheelmounting bracket 224 pivots in a counterclockwise direction 304 (whenviewed from the left hand side in FIG. 12A), thereby moving the wheel226 in a downward direction 306 to engage the floor. On the other hand,when the housing 278 pivots in a counterclockwise direction 310 (whenviewed from the left hand side in FIG. 12A), the connecting link 294moves in a rightward direction 312 toward the wheel mounting bracket224, the wheel mounting bracket 224 pivots in a clockwise direction 314(when viewed from the left hand side in FIG. 12A), thereby moving thewheel 226 in an upward direction 316 above the floor.

As shown in FIG. 12B, the linkage 290 includes a flapper 330 coupled tothe mount 292 for pivoting movement about a pivot pin 332 that extendsgenerally perpendicularly to the axis of rotation 282 of the mount 292between a raised position that corresponds to a raised position of thewheel 226 and a lowered position that corresponds to a lowered positionof the wheel 226. A bent link 334 (FIG. 12A) has a first end pivotablycoupled to the flapper 330 and a second end pivotably coupled to theoutput member 280. As the output member 280 moves between retracted andextended positions, the flapper 330 moves between the raised and loweredpositions through an intermediate overcenter position.

As shown in FIGS. 12A and 12B, the linkage 290 further includes a gasspring 340 that is held in a state of compression between a lug portion342 (FIG. 12B) of the flapper 330 and a flange 344 (FIG. 12A) thatextends downwardly from the rotating platform 206. The lug portion 342is above the axis 282 of the housing 278 of the rotatable actuator 266when the flapper 330 is raised. On the other hand, the lug portion 342is below the axis 282 of the housing 278 when the flapper 330 islowered. Referring to FIG. 12A, when the flapper 330 is between theraised position and the overcenter position, the gas spring 340 biasesthe flapper mount 292 in the counterclockwise direction 310, theconnecting link 294 in the rightward direction 312 toward the wheelmounting bracket 224, the wheel mounting bracket 224 in a clockwisedirection 314, and the wheel 226 in the upward direction 316. On theother hand, when the flapper 330 is between the overcenter position andthe lowered position, the gas spring 340 biases the flapper mount 292 inthe clockwise direction 300, the connecting link 294 in the leftwarddirection 302 away from the wheel mounting bracket 224, the wheelmounting bracket 224 in the counterclockwise direction 304, and thewheel 226 in the downward direction 306.

When the output member 280 of the actuator 266 is retracted, the flapper330 is raised, the gas spring 340 biases the flapper mount 292 in thecounterclockwise direction 310. When the flapper mount 292 is biased inthe counterclockwise direction 310, the connecting link 294 is biased inthe rightward direction 312 toward the wheel mounting bracket 224, thewheel mounting bracket 224 is biased in the clockwise direction 314, andthe wheel 226 is biased in the upward direction 316 away from the floor150. As the output member 280 extends out of the housing 278 in responseto the operation of the motor 262, the flapper 330 moves from the raisedposition to the lowered position. As the flapper 330 moves past theovercenter position toward the lowered position, the gas spring 340biases the flapper mount 292 in the clockwise direction 300, instead ofthe counterclockwise direction 310. When the flapper mount 292 is biasedin the clockwise direction 310, the connecting link 294 is biased in theleftward direction 302 away from the wheel mounting bracket 224, thewheel mounting bracket 224 is biased in the counterclockwise direction304, and the wheel 226 is biased in the downward direction 306 towardthe floor 150. To raise the wheel 226, the sequence is reversed. Thus,the raise/lower motor 262 is operable in response to command signalsfrom the controller 30 to raise the wheel 226 off of the underlyingfloor 150 and to lower the wheel 226 into contact with the floor 150.When the wheel 226 is lowered, it extends through a slot 350 in a cover352 of the device 200 as shown, for example, in FIG. 11.

After the wheel 226 is lowered into contact with the floor 150, theraise/lower motor 262 continues to operate for a specified time intervalto compress the gas spring 340 to increase the downward force exerted bythe wheel 226 against the floor 150 to ensure good traction in order tobe able to move the apparatus 10, even when the apparatus 10 istransporting a heavy patient. By varying the time interval during whichthe raise/lower motor 262 continues to operate after the wheel 226 makesinitial contact with the floor 150, the downward force of the drivingwheel 226 against the floor 150 may be adjusted. Too little engagementforce may result in the slippage of the driving wheel 226. On the otherhand, too much engagement force may lift the apparatus 10 off the floor150. In one embodiment, the downward force exerted by the wheel 226against the floor 150 is increased to about 350 lbs. In anotherembodiment, the armature current of the drive wheel motor 244 is used toadjust the downward force of the wheel 226 against the floor 150. Whenthe wheel 226 is lowered into contact with the floor 150, the contactpoint of the wheel 226 coincides with a point at which the axis ofrotation 208 of the rotating platform 206 intersects the floor 150.

Referring to FIGS. 12A and 12B, the device 200 includes a drive wheelswivel assembly 370 that has a housing 372 coupled to the rotatingplatform 206 for rotation therewith. The swivel assembly 370 includes aswivel motor 374 that is carried by the housing 372 and that operates inresponse to command signals from the controller 30 (FIG. 3). The motor374 has an output shaft 376 that drives a pinion 378 through a worm 380.The pinion 378 is mounted on a vertically-extending shaft 382 thatcarries another pinion (not shown) which engages a ring gear (not shown)attached to the stationary mounting plate 204. The swivel assembly 370includes limit switches 384, 386 mounted on the rotating platform 206.The limit switches 384, 386 are activated by associated stops 388, 390,which are 90° apart, carried by the stationary mounting plate 204. Thepositions of the two stops 388, 390 correspond to the two orientationsof the rotating platform 206, namely, the longitudinal orientation andthe lateral orientation. The activation of the limit switches 384, 386stops the operation of the swivel motor 374. The device 200 is generallyof the type available from Borringia Industrie AG of Ettingen,Switzerland.

As indicated above, the user interface 34 at the head end of apparatus10 includes, for example, the enable switch 44 (FIG. 4) that extendsfrom the distal end 46 of each push handle assembly 50, the forward andreverse switches 52 and 54 (FIGS. 5A and 5B) that are situated within aninterior region of each push handle assembly 50, and the buttons andindicators 70, 76, 78, 80, 82, 84, 86, 88 (FIG. 6) that are coupled tothe handgrip 48 of each push handle assembly 50. An alternative pushhandle assembly 400 is shown in FIGS. 13-15. As shown in FIG. 14, eachpush handle assembly 400 comprises a retaining ring 402, a protectivebumper 404, a mounting bracket 406 that couples to the upper frame 14(FIG. 1) of the apparatus 10, a strain gage assembly 408, a strain gageassembly shield 410, flexible bellows 412, and a push handle 414. Thestrain gage assembly 408, the shield 410, the bellows 412, and the pushhandle 414 are all generally cylindrical elongate tubular members.Although only one push handle assembly 400 is shown in FIGS. 13-15, itis understood that both push handles assemblies 400 are constructedsimilarly with one push handle assembly 400 being substantially themirror image of the other one. Thus, the description that follows of onepush handle assembly 400 is applicable to both.

Referring to FIG. 14, the strain gage assembly 408 includes a mountingtube 430 and a load cell 432 mounted on the opposite sidewalls of themounting tube 430. The load cell 432 performs a function similar to theforward and reverse switches 52, 54 (FIGS. 5A and B). The load cell 432includes four strain gauges or resistors (not shown), which areelectrically connected to form a Wheatstone bridge. Two of the resistorsforming the load cell 432 are located on an inner sidewall of themounting tube 430 and are referred to herein as inner resistors. Two ofthe resistors forming the load cell 432 are located on an outer sidewallof the mounting tube 430 and are referred to herein as outer resistors.The inner and outer resisters forming the load cell 432 arelongitudinally aligned relative to the frame 12. The inner and outerdirections are determined from the vantage point of a user standingadjacent the head end 152 of apparatus 10 and facing toward theapparatus. A load cell 432 of this type is disclosed in U.S. Pat. No.7,090,041, which is hereby entirely incorporated by reference herein.

Electrical wires 436 extend from the load cell 432 (FIG. 20) to acircuit board (not shown) that is situated within an interior region ofthe mounting tube 430. The wires 436 are routed through a pair oflaterally-aligned openings 440 in the opposite sidewalls of the mountingtube 430. Electrical wires (not shown) extending from the circuit boardare routed out of a lower end 442 of mounting tube 430 and are thenrouted to the controller 30 (FIG. 3) along portions of the frame 12. Alower portion 444 of the mounting tube 430 is received in an interiorregion 446 of the mounting bracket 406. In the illustrative embodiment,the mounting tube 430 is rigidly secured to the mounting bracket 406 bya pair of longitudinally-extending bolts (not shown) that extend throughassociated longitudinally-aligned openings 448 in the opposite sidewallsof the mounting bracket 406 and longitudinally-aligned openings 452 inthe opposite sidewalls of the mounting tube 430. The mounting bracket406 is, in turn, fixedly attached to the upper frame 14 by suitablefasteners.

Opposite ends of a laterally-extending pivot pin 460 that extendsthrough a pair of laterally-aligned openings 458 in the sidewalls of themounting tube 430 are received in a pair of laterally-alignedupwardly-opening slots 462 in the opposite sidewalls of the mountingbracket 406. An upper portion 464 of the mounting tube 430 is pivotableor bendable by a slight amount about the laterally-extending pin 460relative to the lower portion 444 of the mounting tube 430 when the pushhandle 414 is pushed forwardly to propel the apparatus 10 forwardly orwhen the push handle 414 is pulled rearwardly to propel the apparatus 10rearwardly. When the push handle 414 is pushed forwardly, the innerresistors forming the load cell 432 are compressed and the outerresistors forming the load cell 432 are stretched to send a first inputsignal to the controller 30 (FIG. 3). On the other hand, when the pushhandle 414 is pulled rearwardly, the inner resistors forming the loadcell 432 are stretched and the outer resistors forming the load cell 432are compressed to send a second input signal to the controller 30 (FIG.3). The mounting tube 430 returns to a neutral position when the userlets go of push handle 414.

The bumper 404 is sleeved over the lower portion 444 of the mountingtube 430 and held in place by the retaining ring 402 that is captured ina circumferential groove 466 formed near the lower end 442 the mountingtube 430. The bumper 404 protects the components of the push handleassembly 400 from accidental or incidental contact with other equipment,such as a push cart. The strain gage assembly shield 410 is sleeved overthe upper portion 464 of the mounting tube 430. Illustratively, themounting tube 430 is made from alloy steel seamless tubing and thebumper 404 is made from suitable elastomeric material. The strain gageassembly 408 shown in FIGS. 13-15 is generally of the type that isavailable from Long Wen Co. of Changzhou, China.

As shown in FIG. 15, the push handle 414 includes a bent tube 500, anenable switch housing 502, an enable switch 504, an enable switchconnector 506, an enable switch actuator 508 (FIG. 14), a handgrip 510,a push handle user interface top housing 512, a push handle userinterface bottom housing 514, and a push handle user interface overlay516. The handgrip 510 is sleeved over a bent portion 478 of the benttube 500 (hereinafter the handle post 478) and coupled thereto bysuitable fasteners, such as screws. Referring to FIG. 14, a lowerportion 480 of the bent tube 500 is received in an upper portion of theinterior region of the mounting tube 430. A longitudinally-extendingpivot pin 484 (FIG. 14) extends through a pair of longitudinally-alignedupwardly-opening slots 486 in the opposite sidewalls of the strain gageshield 410, extends through a pair of longitudinally-aligned openings488 in the opposite sidewalls of the mounting tube 430, and extendsthrough a pair of longitudinally-aligned elongated slots 490 in theopposite sidewalls of the lower portion 480 of the bent tube 500.

To pivot the push handle 414 downwardly to an out-of-the-way stowedposition, the push handle 414 is first pulled upwardly wherein thelongitudinally-extending pin 484 slides within the elongated slots 490in the lower portion 480 of the bent tube 500. The push handle 414 isthen folded downwardly into an inwardly-facing clearance notch 494formed in the upper portion 464 of the mounting tube 430 as shown, forexample, in FIG. 20. To move the push handle 414 back to an upright useposition, the sequence of steps is reversed. The bellows 412 are sleevedover the lower portion 480 of the bent tube 500, the shield 410 and anupper portion of the mounting bracket 406. The bellows 412 coverportions of the push handle assembly 400 without interfering withpivotal movement of the push handle 414 between the folded stowedposition and the upright use position.

Referring to FIGS. 14-15, the enable switch housing 502, the enableswitch 504, the enable switch connector 506, the enable switch actuator508 cooperate to form a push handle enable switch 520, similar to thepush handle enable switch 44 shown in FIGS. 1 and 4. The user interfacetop and bottom housings 512, 514 cooperate to form a user interfacehousing 518. The user interface overlay 516 and the membrane switches530, 540, 542 (FIG. 16) are coupled to the user interface housing 518 toform a push handle user interface 522 (FIGS. 13-15), similar to the pushhandle user interface 34 shown in FIG. 6. In the illustrativeembodiment, the membrane switches 530, 540, 542 are located on theunderside of the user interface overlay 516.

In the illustrative embodiment, the top and bottom housings 512, 514 arearranged on opposite sides of the handle post 478 and coupled togetherby suitable fasteners, such as screws 515 (FIG. 15). As explained laterin conjunction with FIGS. 34-35, the housing 518 has a post or lug 519(FIG. 34) that is received in a radial slot 479 (FIG. 35) formed in thehandle post 478 to limit the rotation of user interface housing 518relative to the handle post 478 (about 90° in the illustrativeembodiment) and to prevent the user interface housing 518 from slippingoff the end of the handle post 478. An O-Ring 526 (FIG. 15) isinterposed between the top and bottom housings 512, 514 of the userinterface 522 and the handle post 478 to provide resistance to therotation of the user interface 522 relative to the handle post 478. Inthe illustrative embodiment, the user interfaces 522 rotate about 90°relative to the respective handle posts 478. In other embodiments,however, the user interface housing 518 may rotate less than or morethan 90° relative to the handle post 478.

As indicated above, each handle post 478 carries the associated userinterface 522 at its distal end. In the illustrative embodiment, 1) inthe plan view, the angle between each handle post 478 and a lateral axis163 is about 30° as shown in FIG. 36, 2) in the end view, the anglebetween each handle post 478 and a horizontal axis 164 is about 44° asshown in FIG. 37, and 3) in the side view, the angle between each handlepost 478 and a longitudinal axis 161 is about 59° as shown in FIG. 38.In other embodiments, these angles may be different. In FIGS. 36-37, theuser interface 522 is facing rearwardly toward a caregiver standing atthe head end 152 of the apparatus 10. In FIG. 38, however, the userinterface is facing upwardly so that a caregiver standing alongside theright side 158 of the apparatus 10 has access to the user interfacecontrols 552.

In the illustrative embodiment, the user interfaces 522 are rotatablymounted to respective handle posts 478. The user interfaces 522 arerotatable about 90° between a position where the user interfaces 522face generally rearwardly, as shown in FIGS. 30 and 36-38, and aposition where the user interfaces 522 face generally upwardly, as shownin FIGS. 31 and 38. As used in the subject specification and claims, theuser interface 522 is facing generally “rearwardly” when the userinterface 522 is facing a caregiver standing at the head end of theapparatus 10 and facing toward the apparatus 10.

As explained later in conjunction with FIGS. 30-33, when the userinterfaces 522 are facing generally rearwardly, as shown in FIGS. 30 and36-38, a caregiver standing at the head end 152 of the apparatus 10 cangrasp one or both handle posts 478 with her hands as shown, for example,in FIG. 32 and operate the membrane switches 530, 540, 542 (collectivelyhereinafter referred to as the push handle user interface controls 552)on one of the push handle user interfaces 522 with her thumb. Likewise,when the user interfaces 522 are facing generally upwardly, as shown inFIGS. 31 and 38, a caregiver standing alongside one of the sides 156,158 of the apparatus 10 can grasp the associated handle post 478 withher hand (as shown, for example, in FIG. 33 with respect to the righthandle post 478) and operate the controls 552 on the push handle userinterface 522 with her thumb from the associated side 156, 158 (asshown, for example, in FIG. 33 with respect to the right side 158).Thus, the rotatable push handle user interfaces 522 allow access to theuser interface controls 552 from both the head end 152 and the sides156, 158 of the apparatus 10.

As shown in FIG. 16, the push handle user interface 522 includes a speedselection button 530 beneath three arcuately arranged speed indicatorLED's 532 near the top of the user interface 522. The speed selectionbutton 530 has an indicia 534 showing a caregiver pushing a stretcher. Aservice required LED 536 is situated to the right of the speed selectionbutton 530. Left and right direction buttons 540, 542 are locatedbeneath the speed selection button 530. A stretcher orientation indicia544 is arranged between the left and right direction buttons 540, 542.Two LED's 546, 548 are provided adjacent the respective left and rightdirection buttons 540, 542. The battery power indicator LED's 550 arelocated beneath the left and right direction buttons 540, 542.Illustratively, the LED's 550 are lit from left to right to indicate theamount of charge in the battery of power supply 36 (FIG. 3). When allLED's 550 are lit, the battery is fully charged and when no LED's 550are lit, the battery is essentially drained of charge.

In the illustrative embodiment, each of buttons 530, 540, 542 comprisesa membrane switch. It is within the scope of this disclosure, however,for other types of buttons or switches to be used, such as rockerswitches, toggle switches, push button switches, and so on, as well asusing a touchscreen or other type of touch sensor, in lieu of themembrane switches that embody buttons 530, 540, 542 in the illustrativeexample. As indicated above, the membrane switches 530, 540, 542 arelocated between the user interface overlay 516 and the housing 518.

Assuming all of the other necessary conditions are met, includingpressing one of the push handle enable switches 520, then pushing one orboth push handles 414 forwardly results in the stretcher 10 beingpropelled forwardly by the powered transport device 200 (FIGS. 11, 12A,and 12B), whereas pulling one or both push handles 414 rearwardlyresults in the stretcher 10 being propelled rearwardly by the poweredtransport device 200. Subsequent Presses of the speed selection button530 (FIG. 16) selectively toggles the speed among a plurality ofdiscrete speed settings at which the drive wheel motor 244 is operable.

Illustratively, in the disclosed example, there are three discrete speedsettings, namely, a slow speed setting, a medium speed setting, and afast speed setting. As such, the user interface 522 has three speedindicator LED's 532 to visually indicate the selected speed setting. Forexample, in the slow speed setting, the left-most LED 532 is on or litand the other two LED's 532 are off or unlit. In the medium speedsetting, the left-most LED 532 and the middle LED 532 are on and theright-most LED 532 is off. In the high speed setting, all three LED's532 are on. Of course, if there are more or less than three speedsettings, a corresponding number of lesser or greater LED's areincluded. In the illustrative embodiment, the speed selection button 530simply scrolls in one direction and then cycles back to the beginning ofthe series after the highest, or the lowest, setting is reached.

Similarly, assuming all of the other necessary conditions are met,including pressing one of the push handle enable switches 520, thenpressing the left direction button 540 results in the apparatus 10 beingpropelled by the powered transport device 200 laterally in the leftdirection, whereas pressing the right direction button 542 results inthe apparatus 10 being propelled by the powered transport device 24laterally in the right direction. In the illustrated example, the leftand right directions are determined from the vantage point of a userstanding adjacent a head end of the apparatus 10 and facing toward theapparatus 10 or from the vantage point of a patient lying in a supine orface up position on the mattress 22 with his head near the head end ofthe apparatus 10. The stretcher orientation indicia 544, located betweenthe direction buttons 540, 542, provides the user with a visualindication as to the direction that the apparatus 10 will be propelledin response to the buttons 540, 542 being pressed as shown in FIG. 16.

In some embodiments, only one of the two push handle assemblies 400,such as the push handle assembly 400 on the right side 158, has the pushhandle user interface 522 while both push handle assemblies 400 have thepush handle enable switch 520 and the strain gage assembly 408. FIG. 17shows an alternative push handle user interface 524, which is similar tothe push handle user interface 522 shown in FIG. 16, except that thespeed selection button 530 is omitted in the push handle user interface524 of FIG. 17. In the FIG. 17 embodiment, the speed of the drive wheelmotor 244 is proportional to the force with which one or both pushhandles 414 (FIG. 12A) are pushed forwardly or pulled rearwardly.

FIG. 18 shows an alternative left siderail user interface 560, which issimilar to the left siderail user interface 34 shown in FIG. 7. The leftsiderail user interface 560 includes left, right, forward, and reversedirection buttons 562, 564, 566, 568 arranged about an indicia 570showing a caregiver standing adjacent a left side 156 of the apparatus10 near a head end 152 thereof. Four LED's 572, 574, 576, 578 arelocated adjacent the respective left, right, forward and reversedirection buttons 562, 564, 566, 568. A service required LED 580 issituated to the upper left of the left, right, forward and reversedirection buttons 562, 564, 566, 568. An enable key button 582 isarranged to the lower left of the left, right, forward and reversedirection buttons 562, 564, 566, 568. An LED 584 is provided adjacentthe enable key button 582. A battery power indicator LED's 586 issituated to the upper right of the left, right, forward and reversedirection buttons 562, 564, 566, 568. Illustratively, the LED's 586 arelit from left to right to indicate the amount of charge in the batteryof power supply 36 (FIG. 3). When all LED's 586 are lit, the battery isfully charged and when no LED's 550 are lit, the battery is essentiallydrained of charge. The buttons 562, 564, 566, 568, 582, the indicia 570,and the LED's 572, 574, 576, 578, 580, 584, 586 are all arranged on agenerally vertically oriented surface 113 of a user interface housing 92coupled to the associated siderail 90. FIG. 19 shows a right siderailuser interface 590 which is mirror image of the left siderail userinterface 560 of FIG. 18.

Assuming all of the other necessary conditions are met, includingpressing one of the push handle enable switches 520, then pressing theleft direction button 562 results in the stretcher 10 being propelled bythe powered transport device 200 laterally in the left direction,whereas pressing the right direction button 564 results in the stretcher10 being propelled by the powered transport device 200 laterally in theright direction. Likewise, assuming all of the other necessaryconditions are met, including pressing one of the push handle enableswitches 520, then pressing the forward direction button 566 results inthe stretcher 10 being propelled forwardly by the powered transportdevice 200, whereas pressing the rearward direction button 568 resultsin the stretcher 10 being propelled rearwardly by the powered transportdevice 200. The stretcher orientation indicia 570, located between thebuttons 562, 564, 566, 568, provides the user with a visual indicationas to the direction that the stretcher 10 will be propelled in responseto the direction buttons 562, 564 being pressed as shown in FIGS. 18 and19.

If the drive wheel 226 is in the first orientation when one of the leftand right direction buttons 540, 542 on the associated push handles 414is pressed simultaneously with the push handle enable switch 520, thenthe controller 30 will command the swivel assembly 370 to move the drivewheel 226 from the first orientation to the second orientation prior tocommanding the drive wheel motor 244 to rotate the wheel 226 to propelthe stretcher 10 leftward or rightward, as the case may be. Likewise, ifthe drive wheel 226 is in the first orientation when one of the left andright direction buttons 562, 564 on a siderail 90 is pressedsimultaneously with the siderail enable key button 582, then thecontroller 30 will command the swivel assembly 370 to move the wheel 226from the first orientation to the second orientation prior to commandingthe drive wheel motor 244 to rotate the wheel 226 to propel thestretcher 10 leftward or rightward, as the case may be.

Similarly, if the drive wheel 226 is in the second orientation when oneof the push handles 414 is pushed forwardly or pulled rearwardlysimultaneously with engaging the push handle enable switch 520, then thecontroller 30 will command the swivel assembly 370 to move the drivewheel 226 from the second orientation to the first orientation prior tocommanding the drive wheel motor 244 to rotate the wheel 226 to propelthe stretcher 10 forwardly or rearwardly, as the case may be. Likewise,if the drive wheel 226 is in the second orientation when one of theforward and rearward direction buttons 566, 568 on a siderail 90 ispressed simultaneously with the siderail enable key button 582, then thecontroller 30 will command the swivel assembly 370 to move the drivewheel 226 from the second orientation to the first orientation prior tocommanding the drive wheel motor 244 to rotate the wheel 226 to propelthe stretcher 10 forwardly or rearwardly, as the case may be.

In some embodiments, the push handle direction buttons 540, 542 (FIGS.16-17) include an enable switch layer so that when one of the pushhandle direction buttons 540, 542 is activated, the enable switchincorporated therein is also activated simultaneously therewith. In suchembodiments, the push handle direction buttons 540, 542 operateindependently of the push handle enable switch 520. In other words, insuch embodiments, there is no need to activate the push handle enableswitch 520 simultaneously with the activation of a push handle directionbutton 540, 542. In some embodiments, activation of a siderail enablekey button 582 (FIGS. 18-19) starts a timer, nominally 10 seconds,during which time the controller 30 (FIG. 3) will respond to activationsof the siderail direction buttons 562, 564, 566, 568 (FIGS. 18-19).Activating a single siderail direction button 562, 564, 566, 568 whilethe timer is running causes the controller 30 to signal the device 200with that direction and low speed. Simultaneous activation of multipledirection buttons 562, 564, 566, 568 causes the controller 30 to signalthe device 200 to stop motion. Similarly, the release of all sideraildirection buttons 562, 564, 566, 568 causes the controller 30 to signalthe device 200 to stop motion. Activation of any of the sideraildirection buttons 562, 564, 566, 568 before the timer expires willrestart the timer. If the timer expires, subsequent activation ofsiderail direction buttons 562, 564, 566, 568 will not cause thecontroller 30 to signal the device 200 to command motion.

Two LED's 546, 548 are located adjacent the respective left and rightdirection buttons 540, 542 on the push handles 414 and are on or litwhen the corresponding button 540, 542 is pressed. Likewise, two LED's572, 574 are located adjacent the respective left and right directionbuttons 562, 564 on the siderails 90 and are on or lit when thecorresponding button 562, 564 is pressed. Similarly, two LED's 576, 578are located adjacent the respective forward and rearward directionbuttons 566, 568 on the siderails 90 and are on or lit when thecorresponding button 566, 568 is pressed.

In some embodiments, however, LED's 546, 548 located adjacent therespective left and right direction buttons 540, 542 on the push handles414 are on or lit when the drive wheel 226 is in the second orientationand are off when the wheel 226 is in the first orientation. Likewise,LED's 572, 574 located adjacent the respective left and right directionbuttons 562, 564 on the siderails 90 are on or lit when the drive wheel226 is in the second orientation and are off when the wheel 226 is inthe first orientation. Similarly, LED's 576, 578 located adjacent therespective forward and rearward direction buttons 566, 568 on thesiderails 90 are on or lit when the drive wheel 226 is in the firstorientation and are off when the wheel 226 is in the second orientation.

In such embodiments, LED's 546, 548, 572, 574, 576, 578 provide a visualindication as to the orientation of the drive wheel 226. Based on thestatus of the LED's 546, 548, 572, 574, 576, 578, a user can determinewhether to expect a slight delay after attempting to propel theapparatus 10 due to the wheel 226 being re-oriented from the firstorientation to the second orientation, or vice versa. In someembodiments, the speed setting in the left and right directions defaultsto the low speed setting regardless of what speed setting is otherwiseselected using the speed selection button 530 (FIG. 16) for the forwardand reverse directions. Of course, having slow, medium, and fastsettings for the left and right directions are contemplated by thisdisclosure.

As indicated above with reference to the push handle assembly 400 shownin FIGS. 13-15, to pivot the push handle 414 downwardly to theout-of-the-way stowed position as shown, for example, in FIG. 20, thepush handle 414 is first pulled upwardly wherein thelongitudinally-extending pivot pin 484 slides within the elongatedvertically-extending straight slots 490 in the lower portion 480 of thebent tube 500 of the push handle 414. The push handle 414 is then foldeddownwardly into the inwardly-facing clearance notch 494 formed in theupper portion 464 of the mounting tube 430 of the strain gage assembly408. The sequence of steps is reversed to move the push handle 414 backto the upright use position. FIGS. 21-25 show portions of an alternativepush handle assembly 600, which is substantially similar to the pushhandle assembly 400 shown in FIGS. 13-15, with a few exceptionsdescribed below. For example, the push handle 414 has helical slots 608,(FIGS. 21-23) instead of straight slots 490 (FIGS. 14-15 and 20). Likereference numerals are used to denote like elements of these push handleassemblies 400, 600. The strain gage shield 410 is omitted in FIGS.20-25 to promote clarity.

As shown in FIGS. 21-23, the push handle assembly 600 includes a taperedsleeve 602 coupled to the lower end 480 of the bent tube 500 of the pushhandle 414. The tapered sleeve 602 is configured to be received in atapered socket 604 (FIGS. 21 and 24-25) formed in the upper portion ofthe interior region of the mounting tube 430 of the strain gage assembly408. The tapered sleeve 602 and the tapered socket 604 have non-lockingtaper angles, such as, for example, 12°. The reception of the taperedsleeve 602 having a non-locking taper in the tapered socket 604 alsohaving non-locking taper reduces rattling between the push handle 414and the mounting tube 430 when the push handle 414 is moved to theupright use position while allowing easy separation of the taperedsleeve 602 from the tapered socket 604 when the push handle 414 ispulled upwardly so that it can be folded downwardly to the stowedposition.

Opposite sidewalls 606 of the tapered sleeve 602 are formed to include apair of elongated generally helical slots 608 as shown in FIGS. 21-23.The longitudinally-extending pivot pin 484 (FIG. 20) extends through theopenings 488 in the opposite sidewalls of the mounting tube 430 andextends through the helical slots 608 in the tapered sleeve 602 attachedto the lower end 480 of the bent tube 500 of the push handle 414. As thepush handle 414 is lowered into the tapered socket 604 to the uprightuse position after it is first moved to a generally vertical positionfrom the folded stowed position, the handgrip 510 of the push handle 414is turned inwardly about a generally vertical axis into a more ergonomicposition for a caregiver. On the other hand, the handgrip 510 of thepush handle 414 is turned outwardly about the generally vertical axiswhen the push handle 414 is pulled upwardly before is pivoted downwardlyto the folded-down stowed position. As shown in FIGS. 22-23, aninwardly-facing cutout 610 is formed in a sidewall 606 of the taperedsleeve 602 attached to the lower end 480 of the bent tube 500 of thepush handle 414 for allowing the wires from the push handle enableswitch 520 and the wires from the push handle user interface 522 to passthrough when the push handle 414 is folded down.

FIGS. 26-29 show an alternative push handle assembly 700, which issubstantially similar to the push handle assembly 400 of FIGS. 13-15,with a few exceptions. For example, each push handle assembly 700includes a single pole double throw (SPDT) switch assembly 702 insteadof the strain gage assembly 408 and the shield 410. The SPDT switchassembly 702 performs a function generally similar to the functionperformed by the forward and reverse switches 52, 54 (FIGS. 5A and 5B)situated within an interior region of the associated push handle 50. Forexample, as indicated above in connection with the switches 52, 54, whenthe push handle 50 is pushed forwardly, the forward switch 52 is movedto an on position from an off position. On the other hand, when the pushhandle 50 is pulled rearwardly, the reverse switch 54 is moved to an onposition from an off position. When the user lets go of the push handle50, it returns to a neutral position having both switches 52, 54 in therespective off positions.

As shown in FIGS. 26-29, each push handle assembly 700 comprises theSPDT switch assembly 702, a bumper 704, a mounting bracket 706 thatcouples to the upper frame 14 (FIG. 1) of the apparatus 10, a mountingtube 708, bellows (similar to the bellows 412 in FIG. 14), a push handle714, a pivot tube 716, a handgrip 718, a push handle enable switch 720(similar to the push handle enable switch 520 shown in FIGS. 14-15), anda push handle user interface 722 (similar to the push handle userinterface 522 shown in FIGS. 14-16). The push handle 714 includes alower straight tube 730 and an upper bent tube 732.

The pivot tube 716 is coupled to an upper portion 734 of the straighttube 730. The switch assembly 702 is received in an interior region of alower portion 736 of the bent tube 732. The lower portion 736 of thebent tube 732 is, in turn, received in an interior region of the pivottube 716. A laterally-extending pivot pin 738 extends through a pair oflaterally-aligned openings 740 in the opposite sidewalls of the pivottube 716, extends through a pair of laterally-aligned openings 742 inthe opposite sidewalls of the lower portion 736 of the bent tube 732,and extends through a laterally-extending opening 778 in the switchhousing 770. The pivot tube 716 and lower portion 736 of the bent tube732 are sized so that the bent tube 732 is pivotable by a slight amountabout the laterally-extending pivot pin 738 when the push handle 714 ispushed forwardly to propel the apparatus 10 forwardly or pulledrearwardly to propel the apparatus 10 rearwardly. As explained below,the bent tube 732, and the switch assembly 702 coupled thereto, arebiased to return to a neutral position when the user lets go of the pushhandle 714. A pair of longitudinally-aligned cutouts 744 are formed inthe opposite sidewalls of the pivot tube 716 to allow the slightpivoting movement of the bent tube 732 relative to the straight tube730.

A lower portion 750 of the straight tube 730 of the push handle 714 isreceived in an interior region of an upper portion 752 of the mountingtube 708. A longitudinally-extending pivot pin 754 extends through apair of longitudinally-aligned openings 756 in the opposite sidewalls ofthe mounting tube 708 and extends through a pair oflongitudinally-aligned elongated slots 758 in the opposite sidewalls ofthe lower portion 750 of the straight tube 730. To pivot the push handle714 downwardly to an out-of-the-way stowed position, the push handle 714is first pulled upwardly wherein the pin 754 slides within the elongatedslots 758 in the lower portion 750 of the straight tube 730. The pushhandle 714 is then folded downwardly into an inwardly-facing clearancenotch 760 formed in the upper portion 752 of the mounting tube 708. Tomove the push handle 714 back to an upright use position, the sequenceof steps is reversed.

As shown in FIGS. 27-29, the switch assembly 702 includes a switchhousing 770, an SPDT switch 772, a slider 774, and retainer 776. Asindicated above, the switch assembly 702 is received in an interiorregion of the lower portion 736 of the bent tube 732 for pivotingmovement therewith about the laterally-extending pivot pin 738. Thelower portion 736 of the bent tube 732 is, in turn, received in aninterior region of the pivot tube 716 coupled to the upper portion 734of the straight tube 730. The housing 770 has a forwardly-facingswitch-receiving cavity 780 for receiving the switch 772. The switch 772has an actuator 782 that extends through a relatively large opening 784in the housing 770 and an opening 786 in the slider 774. The slider 774is received in a downwardly-facing slider-receiving cavity 788 in thehousing 770 for side-to-side movement in a longitudinal direction inresponse to pivoting movement of the bent tube 732 about thelaterally-extending pin 738. The retainer 776 is secured to an undersideof the housing 770 by suitable fasteners to prevent the slider 774 fromfalling off. The slider 774 has laterally-extending outer walls 790 thatabut associated laterally-extending inner walls of the pivot tube 716when lower portion 736 of the bent tube 732 is received in the interiorregion of the pivot tube 716.

The switch assembly 702 includes compression springs (not shown) whichare located in pockets 792 in the housing 770. Each spring is held in astate of compression between a wall of the housing 770 and a laterallyextending inner wall 794 of the slider 774 to bias the bent tube 732,and the switch assembly 702 coupled thereto, to return to a neutral oroff position when the user lets go of the push handle 714. When the pushhandle 714 is pushed forwardly, the slider 774 stays in place while theswitch 772 pivots with the bent tube 732 of the push handle 714 aboutthe laterally-extending pin 738 to cause the actuator 782 of the switch772 to move in a first direction relative to the switch housing 770 tosend a first input signal to the controller 30 (FIG. 3). On the otherhand, when the push handle 714 is pulled rearwardly, the actuator 782 ofthe switch 772 moves in a second opposite direction relative to theswitch housing 770 to send a second input signal to the controller 30.When the user lets go of the push handle 714, the compression springscause to bent tube 732 of the push handle 714, and the switch assembly702 coupled thereto, to return to the neutral or off position.

In some embodiments, the powered transport device 200 (FIGS. 11, 12A and12B) has a transport mode of operation and an adjustment mode ofoperation. The transport mode consists of relatively long movements inthe forward and reverse directions, such as those encountered between apatient room and a diagnostic area. The adjustment mode, on the otherhand, consists of relatively short movements, typically two meters orless, to reposition the apparatus 10 within a patient room. In thetransport mode, the device 200 is typically operable at differentspeeds, whereas, in the adjustment mode, the device 200 is typicallyoperable only at a slow speed for precise positioning of the apparatus10 in the room.

In some embodiments, in the transport mode, the controller 30 (FIG. 3)is configured to latch the activation of the forward and reverseswitches, such as, for example, the forward and reverse switches 52, 54(FIGS. 5A and 5B). Upon such latching and simultaneous activation of apush handle enable switch 520 (FIG. 14), the controller 30 signals thedevice 200 to command motion in the selected direction and at theselected speed. The controller 30 will continue to signal the device 200at this speed and direction even if the latched direction switch 52, 54becomes inactive as long as the push handle enable switch 520 isactivated and as long as a direction switch 52, 54 that opposes thecurrently latched direction is not activated. If a different speed isselected while such motion is underway, the controller 30 will continueto signal motion to the device 200, but at the new speed.

Activation of a direction switch 52, 54 that opposes the currentlylatched direction cancels the latched direction and the controller 30signals the device 200 for motion in the opposite direction at theselected speed. In the event of such a cancellation, a timer is startedwhich prevents latching of the new direction. At this point, thedirection switch 52, 54 will operate in an activate-to-run mode. In thiscase, as soon as the switch 52, 54 is no longer activated, thecontroller 30 signals the device 200 to stop. The timer duration is longenough to bring the apparatus 10 to a stop but not so long as to be anuisance in the event that the user intends sustained motion in the newdirection. In an illustrative embodiment, this is approximately twoseconds. When the timer expires, the latching of the now currentdirection is permitted allowing motion in that direction, at theappropriate speed by maintaining only activation of the push buttonenable switch 520.

When a direction switch 52, 54 and the push button enable switch 520 aresimultaneously activated, a timer, nominally 10 seconds, is reset. Thistimer is reset as long as motion is commanded by the user. If the userceases to command motion, the timer begins to run. Until the timerexpires, the selected speed is remembered so that if a user againcommands motion within the duration of the timer, the controller 30signals the device 200 to initiate motion at the previously selectedspeed. In some embodiments, if the timer expires before the usercommands motion, the controller 30 resets the speed to the default (low)speed. Subsequent commanded motion causes the controller 30 to signalthe device 200 to run at the default speed if a different speed is notselected.

In some embodiments, activation of a siderail enable key button 582FIGS. 18-19) starts a timer, nominally 10 seconds, during which time thecontroller 30 will respond to activations of the siderail directionbuttons 562, 564, 566, 568 (FIGS. 18-19). Activating a single sideraildirection button 562, 564, 566, 568 while the timer is running causesthe controller 30 to signal the device 200 with that direction and lowspeed. Simultaneous activation of multiple direction buttons 562, 564,566, 568 causes the controller 30 to signal the device 200 to stopmotion. Similarly, the release of all siderail direction buttons 562,564, 566, 568 causes the controller 30 to signal the device 200 to stopmotion. Activation of any of the siderail direction buttons 562, 564,566, 568 before the timer expires will restart the timer. If the timerexpires, subsequent activation of siderail direction buttons 562, 564,566, 568 will not cause the controller 30 to signal the device 200 tocommand motion.

In some embodiments, both the left and right push handles 414 near thehead end 152 have user interfaces 522 (FIGS. 16-17) and, in addition,both the left and right siderails 90 have user interfaces 560, 590(FIGS. 18-19). In other embodiments, only the left and right pushhandles 414 have user interfaces 522 (FIGS. 36-37) and the left andright siderail user interfaces 560, 590 are dispensed with. In stillother embodiments, only one push handle 414, such as, for example, thepush handle 414 on the right side 158, has a user interface 522.

As indicated above, each handle post 478 carries the associated userinterface 522 at its distal end. In the illustrative embodiment, 1) inthe plan view, the angle between each handle post 478 and a lateral axis163 is about 30° as shown in FIG. 36, 2) in the end view, the anglebetween each handle post 478 and a horizontal axis 164 is about 44° asshown in FIG. 37, and 3) in the side view, the angle between each handlepost 478 and a longitudinal axis 161 is about 59° as shown in FIG. 38.In other embodiments, these angles may be different. In FIGS. 36-37, theuser interface 522 is facing rearwardly so that a caregiver standing atthe head end 152 of the apparatus 10 has access to the user interfacecontrols 552 as shown in FIG. 32. In FIG. 38, however, the userinterface is facing upwardly so that a caregiver standing alongside theright side 158 of the apparatus 10 has access to the user interfacecontrols 552 as shown in FIG. 33.

The left and right push handle user interfaces 522 are mirror images ofeach other. Thus, the description that follows of the right push handleuser interface 522 is applicable to both. As indicated above, therotatable push handle user interface 522 allows access to the pushhandle user interface controls 552 from both the head end 152 and theleft and right sides 156, 158 of the apparatus 10. This feature isespecially useful where the siderail user interfaces 560, 590 (FIGS.18-19) are dispensed with, since the rotatable push handle userinterfaces 522 provide access to the user interface controls 552 fromboth the head end 152, as well as the left and right sides 156, 158 ofthe apparatus 10, as shown, for example, in FIGS. 32-33, respectively,without requiring siderail user interfaces 560, 590.

In the illustrative embodiment, the user interfaces 522 are rotatableabout 90° between a position where the user interfaces 522 facegenerally rearwardly as shown in FIGS. 30 and 36-37 and a position wherethe user interfaces 522 face generally upwardly as shown in FIGS. 31 and38. As used in the subject specification and claims, the user interface522 is “facing rearwardly” when the user interface 522 is facing acaregiver standing at the head end 152 of the apparatus 10 and facingtoward the apparatus 10. When the user interfaces 522 are facinggenerally rearwardly as shown in FIGS. 30 and 37, the push handle userinterface controls 552 are presented to a caregiver standing at the headend 152 of the apparatus 10 so that she can grasp one or both handleposts 478 with her hands as shown, for example, in FIG. 32 and operatethe push handle controls 552 on one of the push handle user interfaces522 with her thumb. Likewise, when the user interfaces 522 are facinggenerally upwardly as shown in FIGS. 31 and 38, the push handle userinterface controls 552 are presented to a caregiver standing alongsideone of the sides 156, 158 of the apparatus 10 so that she can grasp theassociated handle post 478 with her hand (as shown, for example, in FIG.33 with respect to the right handle post 478) and operate the pushhandle controls 552 on the push handle user interface 522 with her thumbfrom the associated side 156, 158 (as shown, for example, in FIG. 33with respect to the right side 158).

When a caregiver is standing on the right side 158 of the apparatus 10as shown, for example, in FIG. 33, the user interface 522 carried by theright push handle 414 is rotated upwardly and the caregiver grasps theright handle post 478 with her left hand as shown, for example, in FIG.33 and operates the push handle user interface controls 552 with herleft thumb. Likewise, when the caregiver is standing on the left side158 of the apparatus 10, the user interface 522 carried by the left pushhandle 414 is rotated upwardly and the caregiver grasps the left handlepost 478 with her right hand and operates the push handle controls 552with her right thumb.

FIGS. 34-35 are exploded perspective views showing the top and bottomhalves 512, 514 of the user interface housing 518 arranged on oppositesides of the handle post 478 to which they are secured by suitablefasteners, such as screws 515. The handgrip 510 (FIGS. 13-15) is omittedin FIGS. 34-35 to promote clarity. The screws 515 extend throughslightly-oversized openings 800 (FIG. 34) in the bottom housing 514 andthen screwed into respective threaded openings 802 (FIG. 35) in the tophousing 512. The bottom housing 514 has an upwardly-extending post orlug 519 (FIG. 34) that is received in a radial slot 479 (FIG. 35) formedon the back side of the handle post 478. The reception of the post 519in the radial slot 479 in the handle post 478 limits the rotation of theuser interface housing 518 relative to the handle post 478 and, inaddition, prevents the user interface housing 518 from sliding off theend of the handle post 478.

The side edges 810, 812 (FIG. 35) of the radial slot 479 in the handlepost 478 define the generally rearward and generally upward positions ofthe user interface housing 518 shown in FIGS. 30 and 31, respectively.In the illustrative embodiment, the user interface housings 518 rotateabout 90° relative to the respective handle posts 478. In otherembodiments, however, the user interface housings 518 may rotate lessthan or more than 90° relative to the respective handle posts 478. AnO-Ring 526 (FIG. 15) is interposed between the top and bottom housings512, 514 of the user interface 522 and the handle post 478 to provideresistance to the rotation of the user interface 522 relative to thehandle post 478. The top and bottom housings 512, 514 cooperate todefine an annular recess 820 in which the O-ring 526 is captured whenthe top and bottom housings 512, 514 are attached to the handle post478.

In the illustrative embodiment, each push handle 414 comprises a hollowtube. As shown in FIG. 34, the wires 830 from the push handle userinterface controls 552, which are membrane switches in the illustrativeembodiment, are routed from the respective controls 552 through a window832 in the handle post 478 into an interior region 834 of the handlepost 814 and then routed downwardly through the hollow tube. The wires830 are coupled to the controls 552 via a membrane switch connector 836(FIG. 34). The wires 830 exit through an opening in the bottom portionof the push handle 414 and are then routed to the controller 30. Asshown in FIG. 35, the handle post 478 has a slot 840 for receiving theenable switch actuation button 508 (FIG. 14).

Although certain illustrative embodiments have been described in detailabove, variations and modifications exist within the scope and spirit ofthis disclosure as described and as defined in the following claims.

1.-20. (canceled)
 21. A patient support apparatus comprising a frame, aplurality of casters coupled to the frame, a wheel coupled to the frame,a motor coupled to the wheel and operable to rotate the wheel to propelthe patient support apparatus along a floor, the wheel being movablerelative to the frame so as to propel the patient support apparatus indifferent directions relative to a longitudinal dimension of the frame,an electrical system comprising a controller to control operation of themotor, the controller being configured to signal operation of the motorto rotate the wheel to propel the patient support apparatus along thefloor, a push handle situated near a first end of the frame, and aplurality of user inputs coupled to the push handle, a first user inputof the plurality of user inputs being operable by a user to signal thecontroller to operate the motor to propel the patient support apparatusin a first direction parallel with the longitudinal dimension of theframe, and a second user input of the plurality of user inputs beingoperable by a user to signal the controller to operate the motor topropel the patient support apparatus in a second direction that is otherthan the longitudinal dimension relative to the frame, the first userinput being spaced apart from the second user input.
 22. The patientsupport apparatus of claim 21, wherein the electrical system furthercomprises a third user input that is activated by a user to selectivelytoggle among a plurality of discrete speed settings at which the motoris operable.
 23. The patient support apparatus of claim 22, wherein theplurality of discrete speed settings comprises a slow speed setting, amedium speed setting, and a fast speed setting.
 24. The patient supportapparatus of claim 23, wherein at least one of the slow speed setting,the medium speed setting, and the fast speed setting corresponds to afaster speed when the wheel is in the first orientation than in thesecond orientation.
 25. The patient support apparatus of claim 23,wherein at least one of the slow speed setting, the medium speedsetting, and the fast speed setting corresponds to a faster speed whenthe wheel is operated to propel the patient support apparatus in aforward direction than when the wheel is operated to propel the patientsupport apparatus in a reverse direction.
 26. The patient supportapparatus of claim 22, wherein each of the plurality of discrete speedsettings corresponds to a threshold speed up to which the motor isaccelerated to reach over time.
 27. The patient support apparatus ofclaim 21, wherein the electrical system further has a deadman switchthat is required to be activated simultaneously with either the first orsecond user input before the controller operates the motor to propel thepatient support apparatus.
 28. The patient support apparatus of claim27, wherein before the controller operates the motor, the controllermust have been signaled that the casters are unbraked and that a batteryof the patient support apparatus is sufficiently charged.
 29. Thepatient support apparatus of claim 21, wherein the first user inputcomprises a first switch coupled to the push handle and the second userinput comprising a second switch coupled to the push handle.
 30. Thepatient support apparatus of claim 29, wherein the first switch or thesecond switch comprises a membrane switch.
 31. The patient supportapparatus of claim 29, wherein the first and second switches are ofdifferent types.
 32. The patient support apparatus of claim 29, whereinthe push handle comprises a grip portion and a post below the gripportion, the first switch is coupled to the post and the second switchis coupled to the grip portion.
 33. The patient support apparatus ofclaim 21, wherein the electrical system comprises a third user inputthat is adjacent a side of the frame and that is activated by a user tosignal the controller to operate the motor to propel the patient supportapparatus.
 34. The patient support apparatus of claim 21, wherein theelectrical system comprises a third user input adjacent a foot end ofthe frame that is activated by a user to signal the controller tooperate the motor when the wheel is in the first orientation or thesecond orientation.
 35. The patient support apparatus of claim 21,wherein the wheel is movable relative to the frame between a loweredposition engaging the floor and a raised position spaced from the floor.36. The patient support apparatus of claim 21, wherein the push handlecomprises a tube and the first user input is located inside a bottomregion of the tube.
 37. The patient support apparatus of claim 36,further comprising a slider that extends from the bottom region of thetube, the slider activates the first user input in a first directionwhen the push handle is pushed forwardly, and the slider activates thefirst user input in a second direction when the push handle is pulledrearwardly.
 38. The patient support apparatus of claim 37, wherein theslider is spring biased to a neutral position.
 39. The patient supportapparatus of claim 21, wherein the first user input comprises a loadcell mounted to a bottom region of the push handle.
 40. The patientsupport apparatus of claim 39, further comprising a flexible bellowsthat covers a portion of the push handle and a portion of the load cell.41. A patient support apparatus comprising a frame, a plurality ofcasters coupled to the frame, a wheel coupled to the frame, a motorcoupled to the wheel and operable to rotate the wheel to propel thepatient support apparatus along a floor, the wheel being movablerelative to the frame so as to propel the patient support apparatus indifferent directions relative to a longitudinal dimension of the frame,an electrical system comprising a controller to control operation of themotor, the controller being configured to signal operation of the motorto rotate the wheel to propel the patient support apparatus along thefloor, and a plurality of user inputs coupled to the electrical system,a first user input of the plurality of user inputs being operable by auser to signal the controller to operate the motor to propel the patientsupport apparatus in a first direction parallel with the longitudinaldimension of the frame, and a second user input of the plurality of userinputs being operable by a user to signal the controller to operate themotor to propel the patient support apparatus in a second direction thatis other than the longitudinal dimension relative to the frame, thefirst user input being spaced apart from the second user input.